Sanpo-yoshi Communication

Printing Column] Compatibility of Foil and Sumi Ink

What, really?"

It's supposed to react with something in the ink and something in the foil."

This kind of story should only be confirmed in detail.

When we checked with two foil manufacturers, one knew and one did not. We also looked on the Internet, but could not find any details.

The source of the color in black is derived from carbon (coal). The foil film contains aluminum. When heat and humidity conditions are added to that carbon and aluminum, it is said that electrodes are generated (it seems to be the same logic as that of bincho charcoal batteries, etc.).

Foil stamping (hot stamping) uses heat to melt the glue. The conditions of heat, moisture, foil (aluminum), and black color (carbon, coal) are all present, and depending on storage conditions and other factors, the phenomenon of electric corrosion (metal corrodes with electricity) will occur. Since it is a small amount of electricity, it seems to deteriorate over a period of several months to a year.

The way to deal with this is,

1. using insulating foil (microwave-safe foil)
Since aluminum is not used, it does not generate electricity and does not conduct electricity. The disadvantage is that there are only a few types.

2. use "non-carbon black ink" for black printing such as printing
The disadvantage is that it is a little light black.

(3) Prevent contact between the aluminum of the foil and the carbon of the black ink by applying a no-wax type varnish between the foil and the ink.
It is expected to be reduced.

In the process of researching this issue, I learned many new things. I would like to thank the foil manufacturer's staff for their cooperation and the employees who provided me with information.